N-heteroaryl substituted aniline derivatives as HCV-antivirals

ABSTRACT

The present invention discloses compounds of Formula (I): wherein the variables in Formula I are defined as described herein. Also disclosed are pharmaceutical compositions containing such compounds and methods for using the compounds of Formula I in the prevention or treatment of HCV infection.

This application is a National Stage Application of PCT/EP2014/053781filed Feb. 27, 2014, which claims priority from U.S. Provisional PatentApplication No. 61/772,930, filed on Mar. 5, 2013. The priority of bothsaid PCT and U.S. Provisional Patent Application are claimed. Each ofthe prior mentioned applications is hereby incorporated by referenceherein in its entirety.

The present invention provides compounds of Formula I useful asinhibitors of hepatitis C virus (HCV), as inhibitors of HCV infection,and for the prevention and treatment of hepatitis C infection.

Hepatitis C virus (HCV) infection is a major health problem that affects170 million people worldwide and 3-4 million people in the United States(Armstrong, G. L., et al., Ann. Intern. Med. 2006, 144:705-714; Lauer,G. M., et al., N. Eng. J. Med. 2001, 345:41-52). HCV infection leads tochronic liver disease, such as cirrhosis and hepatocellular carcinoma ina substantial number of infected individuals. Chronic HCV infectionassociated liver cirrhosis and hepatocellular carcinoma are also theleading cause of liver transplantation in the United States. Currenttreatments for HCV infection include immunotherapy with pegylatedinterferon-α in combination with the nucleoside-analog ribavirin.Pegylated interferon-α in combination with ribavirin and one of the tworecently approved HCV NS3 protease inhibitors Incivek or Victrelis isthe current standard of care for the treatment of genotype 1 HCVinfected patients, the most difficult to treat patient population.However, current HCV treatments are compromised by suboptimal sustainedvirological response rates and associated with severe side effects, aswell as resistance to the protease inhibitors. Therefore there is aclear need for improved antiviral drugs with better efficacy, safety,and resistance profiles.

The infection of human hepatocytes by HCV, also known as HCV entry, ismediated by the functional interactions of virally-encoded envelopeglycoproteins E1 and E2 and host cell co-receptors, followed by areceptor-mediated endocytosis processes. This HCV entry step is aputative target for therapeutic intervention. Several virally-encodedenzymes are also putati ve targets for therapeutic intervention,including a metalloprotease (NS2-3), a serine protease (NS3, amino acidresidues 1-180), a helicase (NS3, full length), an NS3 protease cofactor(NS4A), a membrane protein (NS4B), a zinc metalloprotein (NSSA) and anRNA-dependent RNA polymerase (NSSB). Systems have been developed tostudy the biology of HCV entry into host cells. Pseudotyping systemswhere the E1 and E2 glycoproteins are used to functionally replace theglycoproteins of retroviruses have been developed (Bartosch, B.,Dubuisson, J. and Cosset, F.-L. J. Exp. Med. 2003, 197:633-642; Hsu, M.et al. Proc. Natl. Acad. Sci. USA. 2003, 100:7271-7276). These systemsyield HCV pseudoparticles that bind to and enter host cells in a mannerwhich is believed to be analogous to the natural virus, thus making thema convenient tool to study the viral entry steps as well as to identifyinhibitors blocking this process.

There is a clear and long-felt need to develop effective therapeuticsfor treatment of HCV infection. Specifically, there is a need to developcompounds that selectively inhibit HCV viral entry and replication andthat are useful for treating HCV-infected patients and protecting livertransplant patients from HCV re-infection. This application disclosesnovel compounds that are effective in prevention of HCV infection.Additionally, the disclosed compounds provide advantages forpharmaceutical uses, for example, with respect to their mechanism ofaction, binding, prevention of infection, inhibition efficacy, andtarget selectivity.

SUMMARY OF THE INVENTION

The application provides compound of formula I

wherein:

R¹ is H, halo, or halo lower alkyl;

R² is H, halo, or R^(2′);

R^(2′) is phenyl, optionally substituted with R^(2″);

R^(2″) is lower alkyl sulfonamido;

R³ is H, halo, or halo lower alkyl;

X is N, NH, or O;

X¹ is N, CH, or O; and

X² is N, CH, or O;

or a pharmaceutically acceptable salt thereof.

The application provides a method for preventing a Hepatitis C Virus(HCV) infection comprising administering to a patient in need thereof atherapeutically effective amount of a compound of Formula I.

The application provides a method for treating a Hepatitis C Virus (HCV)infection comprising administering to a patient in need thereof atherapeutically effective amount of a compound of Formula I.

The application provides a composition comprising a compound of FormulaI and a pharmaceutically acceptable excipient.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

The phrase “a” or “an” entity as used herein refers to one or more ofthat entity; for example, a compound refers to one or more compounds orat least one compound. As such, the terms “a” (or “an”), “one or more”,and “at least one” can be used interchangeably herein.

As used in this specification, whether in a transitional phrase or inthe body of the claim, the terms “comprise(s)” and “comprising” are tobe interpreted as having an open-ended meaning. That is, the terms areto be interpreted synonymously with the phrases “having at least” or“including at least”. When used in the context of a process, the term“comprising” means that the process includes at least the recited steps,but may include additional steps. When used in the context of a compoundor composition, the term “comprising” means that the compound orcomposition includes at least the recited features or components, butmay also include additional features or components.

As used herein, unless specifically indicated otherwise, the word “or”is used in the “inclusive” sense of “and/or” and not the “exclusive”sense of “either/or”.

The term “independently” is used herein to indicate that a variable isapplied in any one instance without regard to the presence or absence ofa variable having that same or a different definition within the samecompound. Thus, in a compound in which R″ appears twice and is definedas “independently carbon or nitrogen”, both R″s can be carbon, both R″scan be nitrogen, or one R″ can be carbon and the other nitrogen.

When any variable occurs more than one time in any moiety or formuladepicting and describing compounds employed or claimed in the presentinvention, its definition on each occurrence is independent of itsdefinition at every other occurrence. Also, combinations of substituentsand/or variables are permissible only if such compounds result in stablecompounds.

The symbols “*” at the end of a bond or “------” drawn through a bondeach refer to the point of attachment of a functional group or otherchemical moiety to the rest of the molecule of which it is a part. Thus,for example:

A bond drawn into ring system (as opposed to connected at a distinctvertex) indicates that the bond may be attached to any of the suitablering atoms.

The term “optional” or “optionally” as used herein means that asubsequently described event or circumstance may, but need not, occur,and that the description includes instances where the event orcircumstance occurs and instances in which it does not. For example,“optionally substituted” means that the optionally substituted moietymay incorporate a hydrogen atom or a substituent.

If a substituent is designated to be “absent”, the substituent is notpresent.

The term “about” is used herein to mean approximately, in the region of,roughly, or around. When the term “about” is used in conjunction with anumerical range, it modifies that range by extending the boundariesabove and below the numerical values set forth. In general, the term“about” is used herein to modify a numerical value above and below thestated value by a variance of 20%.

Certain compounds may exhibit tautomerism. Tautomeric compounds canexist as two or more interconvertable species. Prototropic tautomersresult from the migration of a covalently bonded hydrogen atom betweentwo atoms. Tautomers generally exist in equilibrium and attempts toisolate an individual tautomers usually produce a mixture whose chemicaland physical properties are consistent with a mixture of compounds. Theposition of the equilibrium is dependent on chemical features within themolecule. For example, in many aliphatic aldehydes and ketones, such asacetaldehyde, the keto form predominates while; in phenols, the enolform predominates. Common prototropic tautomers include keto/enol(—C(═O)—CH—⇄—C(—OH)═CH—), amide/imidic acid (—C(═O)—NH—⇄—C(—OH)═N—) andamidine (—C(═NR)—NH—⇄—C(—NHR)═N—) tautomers. The latter two areparticularly common in heteroaryl and heterocyclic rings and the presentinvention encompasses all tautomeric forms of the compounds.

Technical and scientific terms used herein have the meaning commonlyunderstood by one of skill in the art to which the present inventionpertains, unless otherwise defined. Reference is made herein to variousmethodologies and materials known to those of skill in the art. Standardreference works setting forth the general principles of pharmacologyinclude Goodman and Gilman's The Pharmacological Basis of Therapeutics,10^(th) Ed., McGraw Hill Companies Inc., New York (2001). Any suitablematerials and/or methods known to those of skill can be utilized incarrying out the present invention. However, preferred materials andmethods are described. Materials, reagents and the like to whichreference are made in the following description and examples areobtainable from commercial sources, unless otherwise noted.

The definitions described herein may be appended to formchemically-relevant combinations, such as “heteroalkylaryl,”“haloalkylheteroaryl,” “arylalkylheterocyclyl,” “alkylcarbonyl,”“alkoxyalkyl,” and the like. When the term “alkyl” is used as a suffixfollowing another term, as in “phenylalkyl,” or “hydroxyalkyl,” this isintended to refer to an alkyl group, as defined above, being substitutedwith one to two substituents selected from the other specifically-namedgroup. Thus, for example, “phenylalkyl” refers to an alkyl group havingone to two phenyl substituents, and thus includes benzyl, phenylethyl,and biphenyl. An “alkylaminoalkyl” is an alkyl group having one to twoalkylamino substituents. “Hydroxyalkyl” includes 2-hydroxyethyl,2-hydroxypropyl, 1-(hydroxymethyl)-2-methylpropyl, 2-hydroxybutyl,2,3-dihydroxybutyl, 2-(hydroxymethyl), 3-hydroxypropyl, and so forth.Accordingly, as used herein, the term “hydroxyalkyl” is used to define asubset of heteroalkyl groups defined below. The term—(ar)alkyl refers toeither an unsubstituted alkyl or an aralkyl group. The term (hetero)arylor (het)aryl refers to either an aryl or a heteroaryl group.

The term “carbonyl” or “acyl” as used herein denotes a group of formula—C(═O)R wherein R is hydrogen or lower alkyl as defined herein.

The term “ester” as used herein denotes a group of formula —C(═O)ORwherein R is lower alkyl as defined herein.

The term “alkyl” as used herein denotes an unbranched or branched chain,saturated, monovalent hydrocarbon residue containing 1 to 10 carbonatoms. The term “lower alkyl” denotes a straight or branched chainhydrocarbon residue containing 1 to 6 carbon atoms. “C₁₋₁₀ alkyl” asused herein refers to an alkyl composed of 1 to 10 carbons. Examples ofalkyl groups include, but are not limited to, lower alkyl groups includemethyl, ethyl, propyl, i-propyl, n-butyl, i-butyl, t-butyl or pentyl,isopentyl, neopentyl, hexyl, heptyl, and octyl.

When the term “alkyl” is used as a suffix following another term, as in“phenylalkyl,” or “hydroxyalkyl,” this is intended to refer to an alkylgroup, as defined above, being substituted with one to two substituentsselected from the other specifically-named group. Thus, for example,“phenylalkyl” denotes the radical R′R″—, wherein R′ is a phenyl radical,and R″ is an alkylene radical as defined herein with the understandingthat the attachment point of the phenylalkyl moiety will be on thealkylene radical. Examples of arylalkyl radicals include, but are notlimited to, benzyl, phenylethyl, 3-phenylpropyl. The terms “arylalkyl”or “aralkyl” are interpreted similarly except R′ is an aryl radical. Theterms “(het)arylalkyl” or “(het)aralkyl” are interpreted similarlyexcept R′ is optionally an aryl or a heteroaryl radical.

The terms “haloalkyl” or “halo lower alkyl” or “lower haloalkyl” refersto a straight or branched chain hydrocarbon residue containing 1 to 6carbon atoms wherein one or more carbon atoms are substituted with oneor more halogen atoms.

The term “alkylene” or “alkylenyl” as used herein denotes a divalentsaturated linear hydrocarbon radical of 1 to 10 carbon atoms (e.g.,(CH₂)_(n)) or a branched saturated divalent hydrocarbon radical of 2 to10 carbon atoms (e.g., —CHMe- or —CH₂CH(i-Pr)CH₂—), unless otherwiseindicated. Except in the case of methylene, the open valences of analkylene group are not attached to the same atom. Examples of alkyleneradicals include, but are not limited to, methylene, ethylene,propylene, 2-methyl-propylene, 1,1-dimethyl-ethylene, butylene,2-ethylbutylene.

The term “alkoxy” as used herein means an —O-alkyl group, wherein alkylis as defined above such as methoxy, ethoxy, n-propyloxy, i-propyloxy,n-butyloxy, i-butyloxy, t-butyloxy, pentyloxy, hexyloxy, including theirisomers. “Lower alkoxy” as used herein denotes an alkoxy group with a“lower alkyl” group as previously defined. “C₁₋₁₀ alkoxy” as used hereinrefers to an —O-alkyl wherein alkyl is C₁₋₁₀.

The terms “haloalkoxy” or “halo lower alkoxy” or “lower haloalkoxy”refers to a lower alkoxy group, wherein one or more carbon atoms aresubstituted with one or more halogen atoms.

The term “hydroxyalkyl” as used herein denotes an alkyl radical asherein defined wherein one to three hydrogen atoms on different carbonatoms is/are replaced by hydroxyl groups.

The term “sulfinyl” as used herein denotes a —SO— group.

The term “sulfonyl” as used herein denotes a —SO₂— group.

The terms “alkylsulfonyl” and “arylsulfonyl” as used herein refers to agroup of formula —S(═O)₂R wherein R is alkyl or aryl respectively andalkyl and aryl are as defined herein. The term “heteroalkylsulfonyl” asused herein refers herein denotes a group of formula —S(═O)₂R wherein Ris “heteroalkyl” as defined herein.

The term “lower alkyl sulfonylamido” as used herein refers to a group offormula —S(═O)₂NR₂ wherein each R is independently hydrogen or C₁₋₃alkyl, and lower alkyl is as defined herein.

The term “trifluoromethyl sulfonyl” as used herein refers to a group offormula —S(═O)₂CF₃.

The term “trifluoromethyl sulfinyl” as used herein refers to a group offormula —S(═O)CF₃.

The term “trifluoromethyl sulfanyl” as used herein refers to a group offormula —SCF₃.

The term “nitro” as used herein refers to a group of formula —N⁺(═O)O⁻.

The term “carboxyl” as used herein refers to a group of formula —C(═O)R₂wherein each R is independently hydrogen or C₁₋₃ alkyl, and lower alkylis as defined herein.

The term “cycloalkyl” denotes a monovalent saturated monocyclic orbicyclic hydrocarbon group of 3 to 10 ring carbon atoms. In particularembodiments cycloalkyl denotes a monovalent saturated monocyclichydrocarbon group of 3 to 8 ring carbon atoms. Bicyclic means consistingof two saturated carbocycles having one or more carbon atoms in common.Particular cycloalkyl groups are monocyclic. Examples for monocycliccycloalkyl are cyclopropyl, cyclobutanyl, cyclopentyl, cyclohexyl orcycloheptyl. Examples for bicyclic cycloalkyl arebicyclo[2.2.1]heptanyl, or bicyclo[2.2.2]octanyl.

The term “amino” as used herein denotes a group of the formula —NR′R″wherein R′ and R″ are independently hydrogen, alkyl, alkoxy, cycloalkyl,heterocycloalkyl, aryl or heteroaryl. Alternatively, R′ and R″, togetherwith the nitrogen to which they are attached, can form aheterocycloalkyl. The term “primary amino” denotes a group wherein bothR′ and R″ are hydrogen. The term “secondary amino” denotes a groupwherein R′ is hydrogen and R″ is not. The term “tertiary amino” denotesa group wherein both R′ and R″ are not hydrogen. Particular secondaryand tertiary amines are methylamine, ethylamine, propylamine,isopropylamine, phenylamine, benzylamine dimethylamine, diethylamine,dipropylamine and diisopropylamine.

The term “amido” as used herein denotes a group of the formula—C(═O)NR′R″ or —NR′C(═O)R″ wherein R′ and R″ are independently hydrogen,alkyl, alkoxy, cycloalkyl, heterocycloalkyl, aryl or heteroaryl.

The term “heteroaryl” denotes a monovalent aromatic heterocyclic mono-or bicyclic ring system of 5 to 12 ring atoms, comprising 1, 2, 3 or 4heteroatoms selected from N, O and S, the remaining ring atoms beingcarbon. Examples of heteroaryl moieties include pyrrolyl, furanyl,thienyl, imidazolyl, oxazolyl, thiazolyl, triazolyl, oxadiazolyl,thiadiazolyl, tetrazolyl, pyridinyl, pyrazinyl, pyrazolyl, pyridazinyl,pyrimidinyl, triazinyl, azepinyl, diazepinyl, isoxazolyl, benzofuranyl,isothiazolyl, benzothienyl, indolyl, isoindolyl, isobenzofuranyl,benzimidazolyl, benzoxazolyl, benzoisoxazolyl, benzothiazolyl,benzoisothiazolyl, benzooxadiazolyl, benzothiadiazolyl, benzotriazolyl,purinyl, quinolinyl, isoquinolinyl, quinazolinyl, or quinoxalinyl.

The term “heterocycloalkyl” denotes a monovalent saturated or partlyunsaturated mono- or bicyclic ring system of 3 to 9 ring atoms,comprising 1, 2, or 3 ring heteroatoms selected from N, O and S, theremaining ring atoms being carbon. In particular embodiments,heterocycloalkyl is a monovalent saturated monocyclic ring system of 4to 7 ring atoms, comprising 1, 2, or 3 ring heteroatoms selected from N,O and S, the remaining ring atoms being carbon. Examples for monocyclicsaturated heterocycloalkyl are aziridinyl, oxiranyl, azetidinyl,oxetanyl, pyrrolidinyl, tetrahydrofuranyl, tetrahydro-thienyl,pyrazolidinyl, imidazolidinyl, oxazolidinyl, isoxazolidinyl,thiazolidinyl, piperidinyl, tetrahydropyranyl, tetrahydrothiopyranyl,piperazinyl, morpholinyl, thiomorpholinyl, 1,1-dioxo-thiomorpholin-4-yl,azepanyl, diazepanyl, homopiperazinyl, or oxazepanyl. Examples forbicyclic saturated heterocycloalkyl are 8-aza-bicyclo[3.2.1]octyl,quinuclidinyl, 8-oxa-3-aza-bicyclo[3.2.1]octyl,9-aza-bicyclo[3.3.1]nonyl, 3-oxa-9-aza-bicyclo[3.3.1]nonyl, or3-thia-9-aza-bicyclo[3.3.1]nonyl. Examples for partly unsaturatedheterocycloalkyl are dihydrofuryl, imidazolinyl, dihydro-oxazolyl,tetrahydro-pyridinyl, or dihydropyranyl.

Inhibitors of HCV Entry

The application provides a compound of formula I

wherein:

R¹ is H, halo, or halo lower alkyl;

R² is H, halo, or R^(2′);

R^(2′) is phenyl, optionally substituted with R^(2″);

R^(2″) is lower alkyl sulfonamido;

R³ is H, halo, or halo lower alkyl;

X is N, NH, or O;

X¹ is N, CH, or O; and

X² is N, CH, or O;

or a pharmaceutically acceptable salt thereof.

The application provides a compound of formula I, wherein R¹ is Cl.

The application provides a compound of formula I, wherein R³ is Cl.

The application provides a compound of formula I, wherein R¹ is Cl andR³ is Cl.

The application provides a compound of formula I, wherein R² is H orhalo.

The application provides a compound of formula I, wherein R² is H orhalo and R¹ is Cl.

The application provides a compound of formula I, wherein R² is H orhalo and R³ is Cl.

The application provides a compound of formula I, wherein R² is H orhalo, R¹ is Cl and R³ is Cl.

The application provides any of the above compounds of formula I,wherein X¹ is N.

The application provides any of the above compounds of formula I,wherein X is N and X² is O.

The application provides any of the above compounds of formula I,wherein X is O and X² is N.

The application alternatively provides any of the above compounds offormula I, wherein X¹ is CH.

The application provides the above compound of formula I, wherein X isNH and X² is N.

The application alternatively provides any of the above compounds offormula I, wherein X¹ is O.

The application provides the above compound of formula I, wherein X is Nand X² is CH or N.

The application provides a compound selected from the group consistingof:

-   N⁵-(3,5-Dichloro-phenyl)-1H-pyrazole-3,5-diamine;-   N⁵-(3,5-Dichloro-4-fluoro-phenyl)-1H-pyrazole-3,5-diamine;-   (3,5-Dichloro-phenyl)-(5-methyl-[1,3,4]oxadiazol-2-yl)-amine;-   N³-(3-Trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine;-   N⁵-(3,5-Dichloro-phenyl)-[1,2,4]oxadiazole-3,5-diamine;-   N³-(3,5-Dichloro-phenyl)-[1,2,4]oxadiazole-3,5-diamine;-   N⁵-(3-Chloro-5-trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine;-   N³-(3-Chloro-5-trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine;-   N-[4′-(3-Amino-[1,2,4]oxadiazol-5-ylamino)-6′-chloro-2′-trifluoromethyl-biphenyl-3-yl]-methanesulfonamide;-   N-[4′-(5-Amino-[1,2,4]oxadiazol-3-ylamino)-6′-chloro-2′-trifluoromethyl-biphenyl-3-yl]-methanesulfonamide;    and-   N²-(3,5-Dichloro-phenyl)-oxazole-2,5-diamine.

The application provides a method for preventing a Hepatitis C Virus(HCV) infection comprising administering to a patient in need thereof atherapeutically effective amount of a compound of Formula I.

The application provides the above method, further comprisingadministering to a patient in need thereof a therapeutically effectiveamount of an immune system suppressant.

The application provides a method for treating a Hepatitis C Virus (HCV)infection comprising administering to a patient in need thereof atherapeutically effective amount of a compound of Formula I.

The application provides any of the above methods, further comprisingadministering a combination of antiviral agents that inhibitsreplication of HCV.

The application provides any of the above methods, further comprisingadministering an immune system modulator or an antiviral agent thatinhibits replication of HCV, or a combination thereof.

The application provides the above method, wherein the immune systemmodulator is an interferon or a chemically derivatized interferon.

The application provides any of the above methods, further comprisingadministering an immune system modulator or an antiviral agent thatinhibits replication of HCV, or a combination thereof, wherein theantiviral agent is selected from the group consisting of a HCV proteaseinhibitor, a HCV polymerase inhibitor, a HCV helicase inhibitor, a HCVNSSA inhibitor, or any combination thereof.

The application provides a composition comprising a compound of FormulaI and a pharmaceutically acceptable excipient.

The application provides the use of the compound of Formula I in thepreparation of a medicament for the prevention of HCV.

The application provides the use of the compound of Formula I in thepreparation of a medicament for the treatment of HCV.

The application provides any compound, composition, method or use asdescribed herein.

Compounds

Examples of representative compounds encompassed by the presentinvention and within the scope of the invention are provided in thefollowing Table. These examples and preparations which follow areprovided to enable those skilled in the art to more clearly understandand to practice the present invention. They should not be considered aslimiting the scope of the invention, but merely as being illustrativeand representative thereof.

In general, the nomenclature used in this Application is based onAUTONOM™ v.4.0, a Beilstein Institute computerized system for thegeneration of IUPAC systematic nomenclature.

If there is a discrepancy between a depicted structure and a name giventhat structure, the depicted structure is to be accorded more weight. Inaddition, if the stereochemistry of a structure or a portion of astructure is not indicated with, for example, bold or dashed lines, thestructure or portion of the structure is to be interpreted asencompassing all stereoisomers of it.

TABLE I depicts examples of compounds according to generic Formula I:

TABLE I # Nomenclature Structure  1 N⁵-(3,5-Dichloro- phenyl)-1H-pyrazole-3,5-diamine

 2 N⁵-(3,5-Dichloro-4- fluoro-phenyl)-1H- pyrazole-3,5-diamine

 3 (3,5-Dichloro-phenyl)- (5-methyl-[1,3,4] oxadiazol-2-yl)-amine

 4 N³-(3-Trifluoromethyl- phenyl)-[1,2,4] oxadiazole-3,5-diamine

 5 N⁵-(3,5-Dichloro- phenyl)-[1,2,4] oxadiazole-3,5-diamine

 6 N³-(3,5-Dichloro- phenyl)-[1,2,4] oxadiazole-3,5-diamine

 7 N⁵-(3-Chloro-5- trifluoromethyl- phenyl)-[1,2,4]oxadiazole-3,5-diamine

 8 N³-(3-Chloro-5- trifluoromethyl- phenyl)-[1,2,4]oxadiazole-3,5-diamine

 9 N-[4′-(3-Amino-[1,2,4] oxadiazol-5-ylamino)- 6′-chloro-2′-trifluoromethyl- biphenyl-3-yl]- methanesulfonamide

10 N-[4′-(5-Amino-[1,2,4] oxadiazol-3-ylamino)- 6′-chloro-2′-trifluoromethyl- biphenyl-3-yl]- methanesulfonamide

11 N²-(3,5-Dichloro-phenyl)- oxazole-2,5- diamine

SynthesisGeneral Schemes

The following schemes depict general methods for obtaining compounds ofFormula I.

Procedure 1

Procedure 2

Procedure 3

Dosage and Administration

The compounds of the present invention may be formulated in a widevariety of oral administration dosage forms and carriers. Oraladministration can be in the form of tablets, coated tablets, dragées,hard and soft gelatin capsules, solutions, emulsions, syrups, orsuspensions. Compounds of the present invention are efficacious whenadministered by other routes of administration including continuous(intravenous drip) topical parenteral, intramuscular, intravenous,subcutaneous, transdermal (which may include a penetration enhancementagent), buccal, nasal, inhalation and suppository administration, amongother routes of administration. The preferred manner of administrationis generally oral using a convenient daily dosing regimen which can beadjusted according to the degree of affliction and the patient'sresponse to the active ingredient.

A compound or compounds of the present invention, as well as theirpharmaceutically useable salts, together with one or more conventionalexcipients, carriers, or diluents, may be placed into the form ofpharmaceutical compositions and unit dosages. The pharmaceuticalcompositions and unit dosage forms may be comprised of conventionalingredients in conventional proportions, with or without additionalactive compounds or principles, and the unit dosage forms may containany suitable effective amount of the active ingredient commensurate withthe intended daily dosage range to be employed. The pharmaceuticalcompositions may be employed as solids, such as tablets or filledcapsules, semisolids, powders, sustained release formulations, orliquids such as solutions, suspensions, emulsions, elixirs, or filledcapsules for oral use; or in the form of suppositories for rectal orvaginal administration; or in the form of sterile injectable solutionsfor parenteral use. A typical preparation will contain from about 5% toabout 95% active compound or compounds (w/w). The term “preparation” or“dosage form” is intended to include both solid and liquid formulationsof the active compound and one skilled in the art will appreciate thatan active ingredient can exist in different preparations depending onthe target organ or tissue and on the desired dose and pharmacokineticparameters.

The term “excipient” as used herein refers to a compound that is usefulin preparing a pharmaceutical composition, generally safe, non-toxic andneither biologically nor otherwise undesirable, and includes excipientsthat are acceptable for veterinary use as well as human pharmaceuticaluse. The compounds of this invention can be administered alone but willgenerally be administered in admixture with one or more suitablepharmaceutical excipients, diluents or carriers selected with regard tothe intended route of administration and standard pharmaceuticalpractice.

“Pharmaceutically acceptable” means that which is useful in preparing apharmaceutical composition that is generally safe, non-toxic, andneither biologically nor otherwise undesirable and includes that whichis acceptable for veterinary as well as human pharmaceutical use.

A “pharmaceutically acceptable salt” form of an active ingredient mayalso initially confer a desirable pharmacokinetic property on the activeingredient which were absent in the non-salt form, and may evenpositively affect the pharmacodynamics of the active ingredient withrespect to its therapeutic activity in the body. The phrase“pharmaceutically acceptable salt” of a compound means a salt that ispharmaceutically acceptable and that possesses the desiredpharmacological activity of the parent compound. Such salts include: (1)acid addition salts, formed with inorganic acids such as hydrochloricacid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, andthe like; or formed with organic acids such as acetic acid, propionicacid, hexanoic acid, cyclopentanepropionic acid, glycolic acid, pyruvicacid, lactic acid, malonic acid, succinic acid, malic acid, maleic acid,fumaric acid, tartaric acid, citric acid, benzoic acid,3-(4-hydroxybenzoyl)benzoic acid, cinnamic acid, mandelic acid,methanesulfonic acid, ethanesulfonic acid, 1,2-ethane-disulfonic acid,2-hydroxyethanesulfonic acid, benzenesulfonic acid,4-chlorobenzenesulfonic acid, 2-naphthalenesulfonic acid,4-toluenesulfonic acid, camphorsulfonic acid,4-methylbicyclo[2.2.2]-oct-2-ene-1-carboxylic acid, glucoheptonic acid,3-phenylpropionic acid, trimethylacetic acid, tertiary butylacetic acid,lauryl sulfuric acid, gluconic acid, glutamic acid, hydroxynaphthoicacid, salicylic acid, stearic acid, muconic acid, and the like; or (2)salts formed when an acidic proton present in the parent compound eitheris replaced by a metal ion, e.g., an alkali metal ion, an alkaline earthion, or an aluminum ion; or coordinates with an organic base such asethanolamine, diethanolamine, triethanolamine, tromethamine,N-methylglucamine, and the like.

Solid form preparations include powders, tablets, pills, capsules,cachets, suppositories, and dispersible granules. A solid carrier may beone or more substances which may also act as diluents, flavoring agents,solubilizers, lubricants, suspending agents, binders, preservatives,tablet disintegrating agents, or an encapsulating material. In powders,the carrier generally is a finely divided solid which is a mixture withthe finely divided active component. In tablets, the active componentgenerally is mixed with the carrier having the necessary bindingcapacity in suitable proportions and compacted in the shape and sizedesired. Suitable carriers include but are not limited to magnesiumcarbonate, magnesium stearate, talc, sugar, lactose, pectin, dextrin,starch, gelatin, tragacanth, methylcellulose, sodiumcarboxymethylcellulose, a low melting wax, cocoa butter, and the like.Solid form preparations may contain, in addition to the activecomponent, colorants, flavors, stabilizers, buffers, artificial andnatural sweeteners, dispersants, thickeners, solubilizing agents, andthe like.

Liquid formulations also are suitable for oral administration includeliquid formulation including emulsions, syrups, elixirs, aqueoussolutions, aqueous suspensions. These include solid form preparationswhich are intended to be converted to liquid form preparations shortlybefore use. Emulsions may be prepared in solutions, for example, inaqueous propylene glycol solutions or may contain emulsifying agentssuch as lecithin, sorbitan monooleate, or acacia. Aqueous solutions canbe prepared by dissolving the active component in water and addingsuitable colorants, flavors, stabilizing, and thickening agents. Aqueoussuspensions can be prepared by dispersing the finely divided activecomponent in water with viscous material, such as natural or syntheticgums, resins, methylcellulose, sodium carboxymethylcellulose, and otherwell-known suspending agents.

The compounds of the present invention may be formulated for parenteraladministration (e.g., by injection, for example bolus injection orcontinuous infusion) and may be presented in unit dose form in ampoules,pre-filled syringes, small volume infusion or in multi-dose containerswith an added preservative. The compositions may take such forms assuspensions, solutions, or emulsions in oily or aqueous vehicles, forexample solutions in aqueous polyethylene glycol. Examples of oily ornonaqueous carriers, diluents, solvents or vehicles include propyleneglycol, polyethylene glycol, vegetable oils (e.g., olive oil), andinjectable organic esters (e.g., ethyl oleate), and may containformulatory agents such as preserving, wetting, emulsifying orsuspending, stabilizing and/or dispersing agents. Alternatively, theactive ingredient may be in powder form, obtained by aseptic isolationof sterile solid or by lyophilisation from solution for constitutionbefore use with a suitable vehicle, e.g., sterile, pyrogen-free water.

The compounds of the present invention may be formulated for topicaladministration to the epidermis as ointments, creams or lotions, or as atransdermal patch. Ointments and creams may, for example, be formulatedwith an aqueous or oily base with the addition of suitable thickeningand/or gelling agents. Lotions may be formulated with an aqueous or oilybase and will in general also containing one or more emulsifying agents,stabilizing agents, dispersing agents, suspending agents, thickeningagents, or coloring agents. Formulations suitable for topicaladministration in the mouth include lozenges comprising active agents ina flavored base, usually sucrose and acacia or tragacanth; pastillescomprising the active ingredient in an inert base such as gelatin andglycerin or sucrose and acacia; and mouthwashes comprising the activeingredient in a suitable liquid carrier.

The compounds of the present invention may be formulated foradministration as suppositories. A low melting wax, such as a mixture offatty acid glycerides or cocoa butter is first melted and the activecomponent is dispersed homogeneously, for example, by stirring. Themolten homogeneous mixture is then poured into convenient sized molds,allowed to cool, and to solidify.

The compounds of the present invention may be formulated for vaginaladministration. Pessaries, tampons, creams, gels, pastes, foams orsprays containing in addition to the active ingredient such carriers asare known in the art to be appropriate.

The compounds of the present invention may be formulated for nasaladministration. The solutions or suspensions are applied directly to thenasal cavity by conventional means, for example, with a dropper, pipetteor spray. The formulations may be provided in a single or multidoseform. In the latter case of a dropper or pipette, this may be achievedby the patient administering an appropriate, predetermined volume of thesolution or suspension. In the case of a spray, this may be achieved forexample by means of a metering atomizing spray pump.

The compounds of the present invention may be formulated for aerosoladministration, particularly to the respiratory tract and includingintranasal administration. The compound will generally have a smallparticle size for example of the order of five (5) microns or less. Sucha particle size may be obtained by means known in the art, for exampleby micronization. The active ingredient is provided in a pressurizedpack with a suitable propellant such as a chlorofluorocarbon (CFC), forexample, dichlorodifluoromethane, trichlorofluoromethane, ordichlorotetrafluoroethane, or carbon dioxide or other suitable gas. Theaerosol may conveniently also contain a surfactant such as lecithin. Thedose of drug may be controlled by a metered valve. Alternatively theactive ingredients may be provided in a form of a dry powder, forexample a powder mix of the compound in a suitable powder base such aslactose, starch, starch derivatives such as hydroxypropylmethylcellulose and polyvinylpyrrolidine (PVP). The powder carrier will form agel in the nasal cavity. The powder composition may be presented in unitdose form for example in capsules or cartridges of e.g., gelatin orblister packs from which the powder may be administered by means of aninhaler.

When desired, formulations can be prepared with enteric coatings adaptedfor sustained or controlled release administration of the activeingredient. For example, the compounds of the present invention can beformulated in transdermal or subcutaneous drug delivery devices. Thesedelivery systems are advantageous when sustained release of the compoundis necessary and when patient compliance with a treatment regimen iscrucial. Compounds in transdermal delivery systems are frequentlyattached to a skin-adhesive solid support. The compound of interest canalso be combined with a penetration enhancer, e.g., Azone(1-dodecylaza-cycloheptan-2-one). Sustained release delivery systems areinserted subcutaneously into to the subdermal layer by surgery orinjection. The subdermal implants encapsulate the compound in a lipidsoluble membrane, e.g., silicone rubber, or a biodegradable polymer,e.g., polylactic acid.

Suitable formulations along with pharmaceutical carriers, diluents andexcipients are described in Remington: The Science and Practice ofPharmacy 1995, edited by E. W. Martin, Mack Publishing Company, 19thedition, Easton, Pa. A skilled formulation scientist may modify theformulations within the teachings of the specification to providenumerous formulations for a particular route of administration withoutrendering the compositions of the present invention unstable orcompromising their therapeutic activity.

The modification of the present compounds to render them more soluble inwater or other vehicle, for example, may be easily accomplished by minormodifications (salt formulation, esterification, etc.), which are wellwithin the ordinary skill in the art. It is also well within theordinary skill of the art to modify the route of administration anddosage regimen of a particular compound in order to manage thepharmacokinetics of the present compounds for maximum beneficial effectin patients.

The term “therapeutically effective amount” as used herein means anamount required to reduce symptoms of the disease in an individual. Thedose will be adjusted to the individual requirements in each particularcase. That dosage can vary within wide limits depending upon numerousfactors such as the severity of the disease to be treated, the age andgeneral health condition of the patient, other medicaments with whichthe patient is being treated, the route and form of administration andthe preferences and experience of the medical practitioner involved. Fororal administration, a daily dosage of between about 0.01 and about 1000mg/kg body weight per day should be appropriate in monotherapy and/or incombination therapy. A preferred daily dosage is between about 0.1 andabout 500 mg/kg body weight, more preferred 0.1 and about 100 mg/kg bodyweight and most preferred 1.0 and about 10 mg/kg body weight per day.Thus, for administration to a 70 kg person, the dosage range would beabout 7 mg to 0.7 g per day. The daily dosage can be administered as asingle dosage or in divided dosages, typically between 1 and 5 dosagesper day. Generally, treatment is initiated with smaller dosages whichare less than the optimum dose of the compound. Thereafter, the dosageis increased by small increments until the optimum effect for theindividual patient is reached. One of ordinary skill in treatingdiseases described herein will be able, without undue experimentationand in reliance on personal knowledge, experience and the disclosures ofthis application, to ascertain a therapeutically effective amount of thecompounds of the present invention for a given disease and patient.

The pharmaceutical preparations are preferably in unit dosage forms. Insuch form, the preparation is subdivided into unit doses containingappropriate quantities of the active component. The unit dosage form canbe a packaged preparation, the package containing discrete quantities ofpreparation, such as packeted tablets, capsules, and powders in vials orampoules. Also, the unit dosage form can be a capsule, tablet, cachet,or lozenge itself, or it can be the appropriate number of any of thesein packaged form.

Indications and Method of Treatment

Indications

The application provides a method for preventing a Hepatitis C Virus(HCV) infection comprising administering to a patient in need thereof atherapeutically effective amount of a compound of Formula I.

The application provides the above method, further comprisingadministering to a patient in need thereof a therapeutically effectiveamount of an immune system suppressant.

The application provides a method for treating a Hepatitis C Virus (HCV)infection comprising administering to a patient in need thereof atherapeutically effective amount of a compound of Formula I.

The application provides any of the above methods, further comprisingadministering an immune system modulator or an antiviral agent thatinhibits replication of HCV, or a combination thereof.

The application provides the above method, wherein the immune systemmodulator is an interferon or a chemically derivatized interferon.

The application provides any of the above methods, further comprisingadministering an immune system modulator or an antiviral agent thatinhibits replication of HCV, or a combination thereof, wherein theantiviral agent is selected from the group consisting of a HCV proteaseinhibitor, a HCV polymerase inhibitor, a HCV helicase inhibitor, a HCVNSSA inhibitor, or any combination thereof.

Combination Therapy

The compounds of the invention and their isomeric forms andpharmaceutically acceptable salts thereof are useful in treating andpreventing HCV infection alone or when used in combination with othercompounds targeting viral or cellular elements or functions involved inthe HCV lifecycle. Classes of compounds useful in the invention include,without limitation, all classes of HCV antivirals.

For combination therapies, mechanistic classes of agents that can beuseful when combined with the compounds of the invention include, forexample, nucleoside and non-nucleoside inhibitors of the HCV polymerase,protease inhibitors, helicase inhibitors, NS4B inhibitors, NSSAinhibitors and medicinal agents that functionally inhibit the internalribosomal entry site (IRES) and other medicaments that inhibit HCV cellattachment or virus entry, HCV RNA translation, HCV RNA transcription,replication or HCV maturation, assembly or virus release. Specificcompounds in these classes and useful in the invention include, but arenot limited to, macrocyclic, heterocyclic and linear HCV proteaseinhibitors such as telaprevir (VX-950), boceprevir (SCH-503034),narlaprevir (SCH-9005 18), ITMN-191 (R-7227), TMC-435350 (a.k.a.TMC-435), MK-7009, BI-201335, BI-2061 (ciluprevir), BMS-650032,ACH-1625, ACH-1095 (HCV NS4A protease co-factor inhibitor), VX-500, VX-813, PHX-1766, PHX2054, IDX-136, IDX-3 16, ABT-450 EP-0 13420 (andcongeners) and VBY-376; the Nucleosidic HCV polymerase (replicase)inhibitors useful in the invention include, but are not limited to,R7128, PSI-785 1, IDX-184, IDX-102, R1479, UNX-08 189, PSI-6130, PSI-938and PSI-879 and various other nucleoside and nucleotide analogs and HCVinhibitors including (but not limited to) those derived as 2′-C-methylmodified nucleos(t)ides, 4′-aza modified nucleos(t)ides, and 7′-deazamodified nucleos(t)ides. Non-nucleosidic HCV polymerase (replicase)inhibitors useful in the invention, include, but are not limited to,HCV-796, HCV-371, VCH-759, VCH-916, VCH-222, ANA-598, MK-3281, ABT-333,ABT-072, PF-00868554, BI-207127, GS-9190, A-837093, JKT-109, GL-59728and GL-60667.

In addition, compounds of the invention can be used in combination withcyclophyllin and immunophyllin antagonists (e.g., without limitation,DEBIO compounds, NM-811 as well as cyclosporine and its derivatives),kinase inhibitors, inhibitors of heat shock proteins (e.g., HSP90 andHSP70), other immunomodulatory agents that can include, withoutlimitation, interferons (-alpha, -beta, -omega, -gamma, -lambda orsynthetic) such as Intron A, Roferon-A, Canferon-A300, Advaferon,Infergen, Humoferon, Sumiferon MP, Alfaferone, IFN-β, Feron and thelike; polyethylene glycol derivatized (pegylated) interferon compounds,such as PEG interferon-α-2a (Pegasys), PEG interferon-α-2b (PEGIntron),pegylated IFN-α-con1 and the like; long acting formulations andderivatizations of interferon compounds such as the albumin-fusedinterferon, Albuferon, Locteron, and the like; interferons with varioustypes of controlled delivery systems (e.g., ITCA-638, omega-interferondelivered by the DUROS subcutaneous delivery system); compounds thatstimulate the synthesis of interferon in cells, such as resiquimod andthe like; interleukins; compounds that enhance the development of type 1helper T cell response, such as SCV-07 and the like; TOLL-like receptoragonists such as CpG-10101 (actilon), isotorabine, ANA773 and the like;thymosin α-1; ANA-245 and ANA-246; histamine dihydrochloride;propagermanium; tetrachlorodecaoxide; ampligen; IMP-321; KRN-7000;antibodies, such as civacir, XTL-6865 and the like and prophylactic andtherapeutic vaccines such as InnoVac C, HCV E1E2/MF59 and the like. Inaddition, any of the above-described methods involving administering anNSSA inhibitor, a Type I interferon receptor agonist (e.g., an IFN-α)and a Type II interferon receptor agonist (e.g., an IFN-γ) can beaugmented by administration of an effective amount of a TNF-αantagonist. Exemplary, non-limiting TNF-α antagonists that are suitablefor use in such combination therapies include ENBREL, REMICADE, andHUMIRA.

In addition, compounds of the invention can be used in combination withantiprotozoans and other antivirals thought to be effective in thetreatment of HCV infection such as, without limitation, the prodrugnitazoxanide. Nitazoxanide can be used as an agent in combination withthe compounds disclosed in this invention as well as in combination withother agents useful in treating HCV infection such as peginterferon α-2aand ribavirin.

Compounds of the invention can also be used with alternative forms ofinterferons and pegylated interferons, ribavirin or its analogs (e.g.,tarabavarin, levoviron), microRNA, small interfering RNA compounds(e.g., SIRPLEX-140-N and the like), nucleotide or nucleoside analogs,immunoglobulins, hepatoprotectants, anti-inflammatory agents and otherinhibitors of NS5A. Inhibitors of other targets in the HCV lifecycleinclude NS3 helicase inhibitors; NS4A co-factor inhibitors; antisenseoligonucleotide inhibitors, such as ISIS-14803, AVI-4065 and the like;vector-encoded short hairpin RNA (shRNA); HCV specific ribozymes such asheptazyme, RPI, 13919 and the like; entry inhibitors such as HepeX-C,HuMax-HepC and the like; alpha glucosidase inhibitors such ascelgosivir, UT-231B and the like; KPE-02003002 and BIVN 401 and IMPDHinhibitors. Other illustrative HCV inhibitor compounds include thosedisclosed in the following publications: U.S. Pat. Nos. 5,807,876;6,498,178; 6,344,465; and 6,054,472; PCT Patent Application PublicationNos. WO97/40028; WO98/4038 1; WO00/56331, WO02/04425; WO03/007945;WO03/010141; WO03/000254; WO01/32153; WO00/06529; WO00/18231;WO00/10573; WO00/13708; WO01/85172; WO03/037893; WO03/037894;WO03/037895; WO02/100851; WO02/100846; WO99/01582; WO00/09543;WO02/18369; WO98/17679, WO00/056331; WO98/22496; WO99/07734;WO05/073216, WO05/073195 and WO08/021927.

Additionally, combinations of, for example, ribavirin and interferon,may be administered as multiple combination therapy with at least one ofthe compounds of the invention. The present invention is not limited tothe aforementioned classes or compounds and contemplates known and newcompounds and combinations of biologically active agents. It is intendedthat combination therapies of the present invention include anychemically compatible combination of a compound of this inventive groupwith other compounds of the inventive group or other compounds outsideof the inventive group, as long as the combination does not eliminatethe anti-viral activity of the compound of this inventive group or theanti-viral activity of the pharmaceutical composition itself.

Combination therapy can be sequential, that is treatment with one agentfirst and then a second agent (for example, where each treatmentcomprises a different compound of the invention or where one treatmentcomprises a compound of the invention and the other comprises one ormore biologically active agents) or it can be treatment with both agentsat the same time (concurrently). Sequential therapy can include areasonable time after the completion of the first therapy beforebeginning the second therapy. Treatment with both agents at the sametime can be in the same daily dose or in separate doses. Combinationtherapy need not be limited to two agents and may include three or moreagents. The dosages for both concurrent and sequential combinationtherapy will depend on absorption, distribution, metabolism andexcretion rates of the components of the combination therapy as well asother factors known to one of skill in the art. Dosage values will alsovary with the severity of the condition to be alleviated. It is to befurther understood that for any particular subject, specific dosageregimens and schedules may be adjusted over time according to theindividual's need and the judgment of the one skilled in the artadministering or supervising the administration of the combinationtherapy.

The application provides a method for preventing a Hepatitis C Virus(HCV) infection comprising administering to a patient in need thereof atherapeutically effective amount of a compound of Formula I.

The application provides the above method, further comprisingadministering to a patient in need thereof a therapeutically effectiveamount of an immune system suppressant.

The application provides a method for treating a Hepatitis C Virus (HCV)infection comprising administering to a patient in need thereof atherapeutically effective amount of a compound of Formula I.

The application provides any of the above methods, further comprisingadministering an immune system modulator or an antiviral agent thatinhibits replication of HCV, or a combination thereof.

The application provides the above method, wherein the immune systemmodulator is an interferon or a chemically derivatized interferon.

The application provides any of the above methods, further comprisingadministering an immune system modulator or an antiviral agent thatinhibits replication of HCV, or a combination thereof, wherein theantiviral agent is selected from the group consisting of a HCV proteaseinhibitor, a HCV polymerase inhibitor, a HCV helicase inhibitor, a HCVNSSA inhibitor, or any combination thereof.

EXAMPLES

Abbreviations

Commonly used abbreviations include: acetyl (Ac),azo-bis-isobutyrylnitrile (AIBN), atmospheres (Atm),9-borabicyclo[3.3.1]nonane (9-BBN or BBN),2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (BINAP), tert-butoxycarbonyl(Boc), di-tert-butyl pyrocarbonate or boc anhydride (BOC₂O), benzyl(Bn), butyl (Bu), Chemical Abstracts Registration Number (CASRN),benzyloxycarbonyl (CBZ or Z), carbonyl diimidazole (CDI),1,4-diazabicyclo[2.2.2]octane (DABCO), diethylaminosulfur trifluoride(DAST), dibenzylideneacetone (dba), 1,5-diazabicyclo[4.3.0]non-5-ene(DBN), 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU),N,N′-dicyclohexylcarbodiimide (DCC), 1,2-dichloroethane (DCE),dichloromethane (DCM), 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (DDQ),diethyl azodicarboxylate (DEAD), di-iso-propylazodicarboxylate (DIAD),di-iso-butylaluminumhydride (DIBAL or DIBAL-H), di-iso-propylethylamine(DIPEA), N,N-dimethyl acetamide (DMA), 4-N,N-dimethylaminopyridine(DMAP), N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO),1,1′-bis-(diphenylphosphino)ethane (dppe),1,1′-bis-(diphenylphosphino)ferrocene (dppf),1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI),2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline (EEDQ), ethyl (Et), ethylacetate (EtOAc), ethanol (EtOH), 2-ethoxy-2H-quinoline-1-carboxylic acidethyl ester (EEDQ), diethyl ether (Et₂O), ethyl isopropyl ether(EtOiPr), O-(7-azabenzotriazole-1-yl)-N, N,N′N′-tetramethyluroniumhexafluorophosphate acetic acid (HATU), acetic acid (HOAc),1-N-hydroxybenzotriazole (HOBt), high pressure liquid chromatography(HPLC), iso-propanol (IPA), isopropylmagnesium chloride (iPrMgCl),hexamethyl disilazane (HMDS), liquid chromatography mass spectrometry(LCMS), lithium hexamethyl disilazane (LiHMDS), meta-chloroperoxybenzoicacid (m-CPBA), methanol (MeOH), melting point (mp), MeSO₂— (mesyl orMs), methyl (Me), acetonitrile (MeCN), m-chloroperbenzoic acid (MCPBA),mass spectrum (ms), methyl t-butyl ether (MTBE), methyl tetrahydrofuran(MeTHF), N-bromosuccinimide (NBS), n-Butyllithium (nBuLi),N-carboxyanhydride (NCA), N-chlorosuccinimide (NCS), N-methylmorpholine(NMM), N-methylpyrrolidone (NMP), pyridinium chlorochromate (PCC),Dichloro-((bis-diphenylphosphino)ferrocenyl) palladium(II)(Pd(dppf)Cl₂), palladium(II) acetate(Pd(OAc)₂),tris(dibenzylideneacetone)dipalladium(0) (Pd₂(dba)₃), pyridiniumdichromate (PDC), phenyl (Ph), propyl (Pr), iso-propyl (i-Pr), poundsper square inch (psi), pyridine (pyr),1,2,3,4,5-Pentaphenyl-1′-(di-tert-butylphosphino)ferrocene (Q-Phos),room temperature (ambient temperature, rt or RT), sec-Butyllithium(sBuLi), tert-butyldimethylsilyl or t-BuMe₂Si (TBDMS),tetra-n-butylammonium fluoride (TBAF), triethylamine (TEA or Et₃N),2,2,6,6-tetramethylpiperidine 1-oxyl (TEMPO), triflate or CF₃SO₂— (Tf),trifluoroacetic acid (TFA),1,1′-bis-2,2,6,6-tetramethylheptane-2,6-dione (TMHD),O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium tetrafluoroborate(TBTU), thin layer chromatography (TLC), tetrahydrofuran (THF),trimethylsilyl or Me₃Si (TMS), p-toluenesulfonic acid monohydrate (TsOHor pTsOH), 4-Me-C₆H₄SO₂— or tosyl (Ts), andN-urethane-N-carboxyanhydride (UNCA). Conventional nomenclatureincluding the prefixes normal (n), iso (i-), secondary (sec-), tertiary(tert-) and neo have their customary meaning when used with an alkylmoiety. (J. Rigaudy and D. P. Klesney, Nomenclature in OrganicChemistry, IUPAC 1979 Pergamon Press, Oxford.).

General Conditions

Compounds of the invention can be made by a variety of methods depictedin the illustrative synthetic reactions described below in the Examplessection.

The starting materials and reagents used in preparing these compoundsgenerally are either available from commercial suppliers, such asAldrich Chemical Co., or are prepared by methods known to those skilledin the art following procedures set forth in references such as Fieserand Fieser's Reagents for Organic Synthesis; Wiley & Sons: New York,1991, Volumes 1-15; Rodd's Chemistry of Carbon Compounds, ElsevierScience Publishers, 1989, Volumes 1-5 and Supplementals; and OrganicReactions, Wiley & Sons: New York, 1991, Volumes 1-40. It should beappreciated that the synthetic reaction schemes shown in the Examplessection are merely illustrative of some methods by which the compoundsof the invention can be synthesized, and various modifications to thesesynthetic reaction schemes can be made and will be suggested to oneskilled in the art having referred to the disclosure contained in thisapplication.

The starting materials and the intermediates of the synthetic reactionschemes can be isolated and purified if desired using conventionaltechniques, including but not limited to, filtration, distillation,crystallization, chromatography, and the like. Such materials can becharacterized using conventional means, including physical constants andspectral data.

Unless specified to the contrary, the reactions described herein aretypically conducted under an inert atmosphere at atmospheric pressure ata reaction temperature range of from about −78° C. to about 150° C.,often from about 0° C. to about 125° C., and more often and convenientlyat about room (or ambient) temperature, e.g., about 20° C.

Various substituents on the compounds of the invention can be present inthe starting compounds, added to any one of the intermediates or addedafter formation of the final products by known methods of substitutionor conversion reactions. If the substituents themselves are reactive,then the substituents can themselves be protected according to thetechniques known in the art. A variety of protecting groups are known inthe art, and can be employed. Examples of many of the possible groupscan be found in “Protective Groups in Organic Synthesis” by Green etal., John Wiley and Sons, 1999. For example, nitro groups can be addedby nitration and the nitro group can be converted to other groups, suchas amino by reduction, and halogen by diazotization of the amino groupand replacement of the diazo group with halogen. Acyl groups can beadded by Friedel-Crafts acylation. The acyl groups can then betransformed to the corresponding alkyl groups by various methods,including the Wolff-Kishner reduction and Clemmenson reduction. Aminogroups can be alkylated to form mono- and di-alkylamino groups; andmercapto and hydroxy groups can be alkylated to form correspondingethers. Primary alcohols can be oxidized by oxidizing agents known inthe art to form carboxylic acids or aldehydes, and secondary alcoholscan be oxidized to form ketones. Thus, substitution or alterationreactions can be employed to provide a variety of substituentsthroughout the molecule of the starting material, intermediates, or thefinal product, including isolated products.

Preparative Examples Example 1N*5*-(3,5-Dichloro-phenyl)-1H-pyrazole-3,5-diamine (Compound 1)

To a suspension of ethyl 2-cyanoacetimidate hydrochloride (0.769 g, 5.18mmol, Eq: 1.00) in ethanol (8.0 mL), was added 3,5-dichloroaniline (872mg, 5.38 mmol, Eq: 1.04). The reaction was stirred overnight.

The reaction was filtered and the clear yellow filtrate was transferredto a 10-20 mL microwave reaction vessel. Additional 2-3 mL of ethanolwas used to rinse the flasks. Hydrazine (in water) (475 mg, 470 μL, 5.19mmol, Eq: 1.00) was added. No precipitation occurred but the reactionsolution darkened to a gold color. Heated in an oil bath at 80° C.Solution continued to darken on heating.

Cooled to room temperature after 5 hours. An aliquot was removed anddiluted with acetonitrile and water. The product did appear to bepresent as well as other components. Returned the reaction vessel to theoil bath, increased the bath temperature to 85-90° C. and heated foranother hour. Cooled slowly to room temperature as the oil bath cooledand then stirred overnight at room temperature.

Heated another 2.5 hours at 85° C. Cooled to room temperature. Removedanother aliquot and diluted it with acetonitrile and water. The LC/MSshowed no improvement in the amount of desired products relative to theother components in the reaction mixture.

Concentrated the entire reaction. Partitioned the residue between EtOAcand water. The aqueous phase was washed with a second portion of EtOAc.Each organic phase was washed with brine, dried (Na₂SO₄) andconcentrated. Only a very small amount of material was present in thesecond organic phase (˜50 mg). The majority of the material was in thefirst organic phase (1.35 g; brown oil). The crude organic phase waspurified by flash chromatography (silica gel, SF15-24 g, 70% to 100%EtOAc in hexanes gradient over 5 minutes) to give 296 mg of desiredproduct as a brown oil with impurities.

The material was purified a second time using HPLC (reverse phase,Sunfire Prep C18 OBD [5 uM; 30×100 mm], 10% to 95% acetonitrile in water(each containing 0.1% formic acid)). The purification required multipleruns. The product-containing fractions from each run were combined,concentrated and freeze-dried.

The freeze-dried material was dissolved in EtOAc and washed with aqueousNaHCO₃ (to neutralize the formic acid salt), water and brine. Theorganic phase was dried (Na₂SO₄), concentrated and then freeze-dried togive desired product with trace impurities. The free base was dissolvedin water and treated with 1 equivalent of HCl. This solution was thenfreeze-dried to give an amorphous solid. The HCl salt was taken up inEtOAc and washed with aqueous NaHCO₃ (1×) and water (2×). The organicphase was dried (Na₂SO₄) and concentrated. The residue was taken up inacetonitrile-water and freeze-dried to give 29 mg (2%) of desiredproduct as a light-brown solid.

MS m/z 243, 245 [M+H]

Example 2 N*5*-(3,5-Dichloro-4-fluoro-phenyl)-1H-pyrazole-3,5-diamine(Compound 2)

To a suspension of ethyl 2-cyanoacetimidate hydrochloride (0.50 g, 3.36mmol, Eq: 1.00) in ethanol (5.2 mL), was added3,5-dichloro-4-fluoroaniline (606 mg, 3.36 mmol, Eq: 1.00). Thesuspension was stirred overnight at room temperature, under a nitrogenatmosphere.

The reaction mixture was filtered to remove the salts. The clear yellowfiltrate was then treated with hydrazine (in water) (313 mg, 310 μL,3.42 mmol, Eq: 1.02) and heated in an oil bath at 80-85° C. for 4.5 h.The reaction was cooled to room temperature and concentrated. Theresidue was partitioned between EtOAc and water. The organic phase wasremoved, washed with brine, dried (Na₂SO₄) and concentrated over celite.The crude material was purified by flash chromatography (silica gel,SF15-24 g, 20% to 100% EtOAc in hexanes) to give a light brown oil,which was further purified by HPLC (reverse phase, Sunfire Prep C18 OBD[5 uM; 30×100 mm], 5% to 95% acetonitrile in water (each containing 0.1%TFA)). The product-containing fractions were combined and freeze-dried.The freeze-dried material was taken up in EtOAc and washed with aqueousNaHCO₃ (1×) and water (2×). The organic phases was dried (Na₂SO₄) andconcentrated. The residue was dissolved in acetonitrile-water andfreeze-dried to give 45 mg (5%) of desired product as an off-whitesolid.

MS m/z 261, 263 [M+H]

Example 3 (3,5-Dichloro-phenyl)-(5-methyl-[1,3,4]oxadiazol-2-yl)-amine(Compound 3)

In a 5 mL microwave tube, 2-bromo-5-methyl-1,3,4-oxadiazole (200 mg,1.23 mmol, Eq: 0.05), Tris(dibenzylideneacetone)dipalladium(0) (56.2 mg,61.4 μmol, Eq: 0.05) and(R)-(+)-2,2′-bis(diphenylphosphino)-1,1′-binaphthyl (38.2 mg, 61.4 μmol,Eq: 0.05) were combined with toluene (10.0 ml) to give a brownsuspension. Sodium tert-butoxide (236 mg, 2.45 mmol, Eq: 2.00) and3,5-dichloroaniline (199 mg, 1.23 mmol, Eq: 1.00) were added. Thesolution was degassed with argon for 5 min, heated to 140° C. for 30 minunder microwave.

The mixture was cooled and diluted with 20 mL H₂O, extracted with EtOAc(30×2 mL), and dried over anhydrous Na₂SO₄. Purification by preparativeTLC (Hexanes/EtOAc=30/70) gave 35 mg (12%) of desired product as anoff-white solid 35 mg. MH+ 244.0

Example 4 N*3*-(3-Trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine(Compound 4)

(Z)-methyl N′-cyano-N-(3-(trifluoromethyl)phenyl)carbamimidothioate

To a solution of sodium cyanamide (126 mg, 3 mmol) in MeOH (2 mL), wasadded sodium methoxide (0.5M solution in MeOH, 6 mL, 3 mmol). Thesolution was stirred at room temperature for 20 minutes, after which3-trifluoromethyl isothiocyanate (457 uL, 610 mg, 3 mmol) was added. Thesolution was stirred for 2 hours. Methyl iodide (374 uL, 853 mg, 6 mmol)was added and the reaction mixture was stirred overnight at room temp.The resulting suspension was filtered and the solid was washed with coldmethanol and hexanes and dried to give 617 mg (95%) of desired productas a white solid.

N*3*-(3-Trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine (Compound4)

Sodium methanolate (9.26 ml, 4.63 mmol, Eq: 3.00) was added into a solidhydroxylamine hydrochloride (322 mg, 4.63 mmol, Eq: 3.00) at rt. Stirredat rt for 0.5 hrs, a solution of (Z)-methylN′-cyano-N-(3-(trifluoromethyl)phenyl)carbamimidothioate (400 mg, 1.54mmol, Eq: 1.00) in ethanol was added and the mixture was heated to 63°C. overnight.

The crude mixture was evaporated to dryness, redissolved in hot EtOAcand washed with water. The organic extracts were dried over sodiumsulfate, concentrated, and purified by preparative TLC (silica gel, 1.0mm, 3% MeOH/DCM) to give 296 mg (55%) of desired product as a whitesolid.

¹H NMR (300 MHz, METHANOL-d₄) ppm 7.19 (d, J=7.55 Hz, 1 H) 7.43 (t,J=7.90 Hz, 1 H) 7.59 (d, J=8.69 Hz, 1 H) 7.76 (s, 1 H)

Example 5 N*5*-(3,5-Dichloro-phenyl)-[1,2,4]oxadiazole-3,5-diamine(Compound 5)

In a 5 mL microwave vial, (Z)-methylN′-cyano-N-(3,5-dichlorophenyl)carbamimidothioate (156 mg, 0.6 mmol, Eq:1.00) and N,O-bis(trimethylsilyl)hydroxylamine (160 mg, 900 μmol, Eq:1.5) were combined with CCl4 (1 ml) to give a colorless suspension whichwas capped and heated in a 80° C. oil bath for 2.5 hr. The mixture wasconcentrated in vacuo and MeOH added. The mixture was stirred at RT for18 hours. The reaction mixture was concentrated in vacuo and the crudematerial was purified by preparative TLC (silica gel, 1.0 mm, 9:1DCM/MeOH) to give product which was recrystallized from MeOH and driedin vacuo (89° C., 2 torr, overnight) to give 32 mg (22%) of desiredproduct as a light brown solid.

¹H NMR (300 MHz, DMSO-d₆) ppm 6.19 (s, 2 H) 7.23 (s, 1 H) 7.61 (d,J=1.51 Hz, 2 H) 10.63-11.46 (m, 1 H)

Example 6 N*3*-(3,5-Dichloro-phenyl)-[1,2,4]oxadiazole-3,5-diamine(Compound 6)

In a 5 mL microwave vial, (Z)-methylN′-cyano-N-(3,5-dichlorophenyl)carbamimidothioate (156 mg, 0.6 mmol, Eq:1.00), hydroxylamine hydrochloride (347 mg, 5 mmol, Eq: 8.33) andtriethylamine (506 mg, 697 μl, 5 mmol, Eq: 8.33) were combined with DMF(6 ml) to give a white suspension. The vial capped and stirred in a 50°C. oil bath for 3.5 hours. The reaction was concentrated in vacuo andthe crude material was purified by preparative TLC (silica gel, 1.0 mm,9:1 DCM/MeOH) to give product, was recrystallized from EtOH then driedin vacuo (80° C., 2 torr, overnight) to give 15 mg (10%) of desiredproduct as a white solid.

¹H NMR (300 MHz, DMSO-d₆) ppm 7.06 (t, J=1.70 Hz, 1 H) 7.44 (d, J=1.51Hz, 2 H) 7.79 (s, 2 H) 9.77 (s, 1 H)

Example 7N-5-(3-Chloro-5-trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine(Compound 7)

1-Chloro-3-isothiocyanato-5-trifluoromethyl-benzene

To a cold (0° C.) suspension of 3-chloro-5-(trifluoromethyl)aniline (1g, 5.11 mmol, Eq: 1.00) and calcium carbonate (1.02 g, 10.2 mmol, Eq: 2)in water (11.1 ml) and dichloromethane (11.1 ml) was added thiophosgene(647 mg, 430 μl, 5.62 mmol, Eq: 1.1).

The biphasic reaction mixture was allowed to warm to room temperatureand was vigorously stirred for 16 h. 1N HCl (10 mL) was added and thereaction mixture was pardoned between water and EtOAc. The organic layerwas washed with water and brine, adsorbed unto silica (3 g), andpurified on silica gel (column 40 g, hexane/AcOEt 1:0 to 85:15) to give880 mg (72%) of the desired product as a colorless oil.

Methyl N-3-chloro-5-(trifluoromethyl)phenyl-N-cyanocarbamimidothioate

To a solution of 1-chloro-3-isothiocyanato-5-(trifluoromethyl)benzene(875 mg, 3.68 mmol, Eq: 1.00) in methanol dry (11.1 ml) was added sodiumhydrogencyanamide (248 mg, 3.87 mmol, Eq: 1.05). The light yellowsolution was stirred 30 min at room temperature then iodomethane (1.05g, 512 μl, 7.36 mmol, Eq: 2) was added and the reaction mixture wasstirred 3 h at room temperature. The clear reaction mixture was adsorbedunto silica (2 g), concentrated and purified on silica gel (silica 40 g,dichloromethane/AcOEt 100:0 to 80:20) to give 800 mg (74%) of thedesired product as white solid.

N-5-(3-Chloro-5-trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine(Compound 7)

To a mixture of methylN-3-chloro-5-(trifluoromethyl)phenyl-N-cyanocarbamimidothioate (200 mg,681 μmol, Eq: 1.00) and triethylamine (241 mg, 335 μl, 2.38 mmol, Eq:3.5) in dry methanol (4.97 ml) was added hydroxylamine hydrochloride(142 mg, 2.04 mmol, Eq: 3). The reaction mixture was stirred at 50 C for5 h then concentrated in vacuo and triturated with dichloromethane. Theprecipitate was filtered and washed with dichloromethane, leading to 81mg (42%) ofN-3-(3-Chloro-5-trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine asa white solid. The filtrate contained isomeric product as described inthe subsequent procedure. NMR (DMSO d6, 300 MHz): 9.92 (s, 1H), 7.80 (s,2H); 7.74 (s, 1H); 7.69 (s, 1H); 7.29 (s, 1H).

MS+m/z: 278.9 (M+H)⁺

Example 8N-3-(3-Chloro-5-trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine(Compound 8)

To a mixture of methylN-3-chloro-5-(trifluoromethyl)phenyl-N-cyanocarbamimidothioate (200 mg,681 μmol, Eq: 1.00) and triethylamine (241 mg, 335 μl, 2.38 mmol, Eq:3.5) in dry methanol (4.97 ml) was added hydroxylamine hydrochloride(142 mg, 2.04 mmol, Eq: 3). The reaction mixture was stirred at 50 C for5 h then concentrated in vacuo and triturated with dichloromethane. Theprecipitate was filtered and washed with dichloromethane, leading toisomeric product (described in the previous procedure) ofN-3-(3-Chloro-5-trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine asa white solid. The filtrate contained the desired product. The filtratewas dried in vacuo and purified on silica gel (silica 20 g,dichloromethane/AcOEt 100:0 to 50:50) to give 10 mg (6%) ofN-5-(3-Chloro-5-trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine asa yellow solid.

NMR (DMSO d6, 300 MHz): 11.1 (s, 1H), 7.95 (s, 1H); 7.80 (s, 1H); 7.48(s, 1H); 6.18 (s, 2H).

MS+m/z: 278.9 (M+H)⁺

Example 9N-(4′-(3-amino-1,2,4-oxadiazol-5-ylamino)-2′-chloro-6′-(trifluoromethyl)biphenyl-3-yl)methanesulfonamide(Compound 9)

4-bromo-3-chloro-5-(trifluoromethyl)aniline

To a mixture of 3-chloro-5-(trifluoromethyl)aniline (3.25 g, 16.6 mmol,Eq: 1.00) in dimethylsulfoxide (43.4 ml) was added N-bromosuccinimide(3.11 g, 17.4 mmol, Eq: 1.05) in 5 portions over 2.5 hr (622 mg each 30min). 2 h after the last addition, the reaction mixture was partitionedbetween 10% aqueous sodium sulfite and ethyl acetate. The organic layerwas washed with aqueous sat. sodium carbonate, water (3 times) and brinethen adsorbed unto silica (6 g) and purified on silica gel (column 120g, Hexane/ethyl acetate 90:10 to 65:35) to give 4.36 g (96%) of a yellowsolid.

MS+m/z: 275.8 (M+H)⁺

N-(4′-amino-2′-chloro-6′-(trifluoromethyl)biphenyl-3-yl)methanesulfonamide

A mixture of 4-bromo-3-chloro-5-(trifluoromethyl)aniline (573 mg, 2.09mmol, Eq: 1.00), 3-(methylsulfonamido)phenylboronic acid (529 mg, 2.46mmol, Eq: 1.18) and tetrakis(triphenylphosphine)palladium (0) (211 mg,183 μmol, Eq: 0.0875) was degassed (vacuum/nitrogen cycles) thendegassed dioxane (6.87 ml) (nitrogen bubbling with sonication) and adegassed (nitrogen bubbling with sonication) 2M solution of sodiumcarbonate in water (1.83 ml, 3.66 mmol, Eq: 1.75) were added. Themixture was stirred at 100° C. for 18 h. The reaction mixture wasadsorbed unto silica (2 g), concentrated and purified on silica gel(silica 40 g, dichloromethane/ethyl acetate 100:0 to 80:20) to give 574mg (75%) of the desired product as a yellow solid.

MS+m/z: 365.0 (M+H)⁺

N-(2′-chloro-4′-isothiocyanato-6′-(trifluoromethyl)biphenyl-3-yl)methanesulfonamide

To a cold (0° C.) suspension ofN-(4′-amino-2′-chloro-6′-(trifluoromethyl)biphenyl-3-yl)methanesulfonamide(570 mg, 1.56 mmol, Eq: 1.00) and calcium carbonate (313 mg, 3.13 mmol,Eq: 2) in dichloromethane (3.38 ml) and water (3.38 ml) was addedthiophosgene (198 mg, 131 μl, 1.72 mmol, Eq: 1.1). The reaction mixturewas allowed to warm up to room temperature and was vigorously stirredfor 16 h. 1N HCl was added to adjust the pH to ca. 2. The reactionmixture was partitioned between water and ethyl acetate. The organiclayer was separated and washed with water then brine and purified onsilica gel (column 24 g, dichloromethane/ethyl acetate 1:0 to 85:15) togive 565 mg (89%) of the desired product as a colorless oil.

(E)-methylN-2-chloro-3′-(methylsulfonamido)-6-(trifluoromethyl)biphenyl-4-yl-N′-cyanocarbamimidothioate

To a solution ofN-(2′-chloro-4′-isothiocyanato-6′-(trifluoromethyl)biphenyl-3-yl)methanesulfonamide(560 mg, 1.38 mmol, Eq: 1.00) in dry methanol (5 ml) was added sodiumhydrogencyanamide (92.5 mg, 1.45 mmol, Eq: 1.05). The reaction mixturewas stirred 30 min at room temperature then iodomethane (408 mg, 200 μl,2.87 mmol, Eq: 2.09) was added and the reaction mixture was stirred 1 h30 at room temperature then adsorbed unto silica (1 g), concentrated andpurified on silica gel (silica 24 g, dichloromethane/ethyl acetate 100:0to 60:40) to give 436 mg (68%) of the desired product as a yellow foam.

N-(4′-(3-amino-1,2,4-oxadiazol-5-ylamino)-2′-chloro-6′-(trifluoromethyl)biphenyl-3-yl)methanesulfonamide(Compound 9)

To a mixture of (E)-methylN-2-chloro-3′-(methylsulfonamido)-6-(trifluoromethyl)biphenyl-4-yl-N′-cyanocarbamimidothioate(330 mg, 713 μmol, Eq: 1.00) and triethylamine (130 mg, 180 μl, 1.28mmol, Eq: 1.8) in THF dry (2.49 ml) was added hydroxylamine.hydrochloricacid (74.3 mg, 1.07 mmol, Eq: 1.5). The reaction mixture was stirred atRT for 3 days then triethylamine (259 mg, 360 μl, 2.56 mmol, Eq: 3.59)and hydroxylamine.hydrochloric acid (140 mg, 2.01 mmol, Eq: 2.83) wereadded and the reaction mixture was stirred for an additional 16 h at RT.

The precipitate was filtered and washed with THF. The white solid wasdiscarded.

The liquor was adsorbed unto silica (2 g) concentrated to dryness, andpurified on silica gel (column 40 g, gradient dichloromethane/methanol98:2 to 70:30) to give less polar fraction containing 84 mg (26%) ofdesired product,N-(4′-(3-amino-1,2,4-oxadiazol-5-ylamino)-2′-chloro-6′-(trifluoromethyl)biphenyl-3-yl)methanesulfonamide.The more polar fraction contained isomeric product,N-(4′-(5-amino-1,2,4-oxadiazol-3-ylamino)-2′-chloro-6′-(trifluoromethyl)biphenyl-3-yl)methanesulfonamide,described in the subsequent procedure.

NMR (DMSO d6, 300 MHz): 11.11 (s, 1H), 9.87 (s, 1H); 8.13 (s, 1H); 7.92(s, 1H); 7.42 (t, J=8 Hz, 1H); 7.25 (broad d, J=8 Hz, 1H); 7.07 (broads, 1H); 6.95 (broad d, J=8 Hz, 1H); 6.2 (s, 2H); 2.96 (s, 3H).

MS+m/z: 447.9 (M+H)⁺

Example 10N-(4′-(5-amino-1,2,4-oxadiazol-3-ylamino)-2′-chloro-6′-(trifluoromethyl)biphenyl-3-yl)methanesulfonamide(Compound 10)

To a mixture of (E)-methylN-2-chloro-3′-(methylsulfonamido)-6-(trifluoromethyl)biphenyl-4-yl-N′-cyanocarbamimidothioate(330 mg, 713 μmol, Eq: 1.00) and triethylamine (130 mg, 180 μl, 1.28mmol, Eq: 1.8) in THF dry (2.49 ml) was added hydroxylamine.hydrochloricacid (74.3 mg, 1.07 mmol, Eq: 1.5). The reaction mixture was stirred atRT for 3 days then triethylamine (259 mg, 360 μl, 2.56 mmol, Eq: 3.59)and hydroxylamine.hydrochloric acid (140 mg, 2.01 mmol, Eq: 2.83) wereadded and the reaction mixture was stirred for an additional 16 h at RT.The precipitate was filtered and washed with THF. The white solid wasdiscarded. The filtrate was adsorbed unto silica (2 g) concentrated todryness, and purified on silica gel (column 40 g, gradientdichloromethane/methanol 98:2 to 70:30) to give a more polar fractioncontaining 76 mg (24%) of desired product,N-(4′-(5-amino-1,2,4-oxadiazol-3-ylamino)-2′-chloro-6′-(trifluoromethyl)biphenyl-3-yl)methanesulfonamide.The less polar fractions were isomeric product,N-(4′-(3-amino-1,2,4-oxadiazol-5-ylamino)-2′-chloro-6′-(trifluoromethyl)biphenyl-3-yl)methanesulfonamide,as described in the previous procedure.

NMR (DMSO d6, 300 MHz): 9.97 (s, 1H), 9.86 (s, 1H); 7.95-7.77 (m, 4H);7.42 (t, J=8 Hz, 1H); 7.24 (broad d, J=8 Hz, 1H); 7.03 (broad s, 1H);6.94 (broad d, J=8 Hz, 1H); 2.97 (s, 3H).

MS+m/z: 447.9 (M+H)⁺

Biological Examples

Determination of compounds HCV GT1b and GT1a entry inhibitory activityusing the pseudotyped HCV particle (HCVpp) reporter assay.

Mammalian expression plasmids for the generation of pseudotyped virusparticles.

Plasmids expressing HCV E1 and E2 envelope proteins of GT1a H77 strain(Proc Natl Acad Sci USA 1997 94:8738-43) or GT1b Con1 strain (Science1999 285:110-3) were constructed by cloning the nucleic acids encodingthe last 60 amino acids of HCV core protein and all of the HCV E1 and E2proteins into pcDNA3.1(+) vector. Plasmid pVSV-G expressing theglycoprotein G of the vesicular stomatitis virus (VSV G) is fromClontech (cat #631530). The HIV packaging construct expressing thefirefly luciferase reporter gene was modified based on the envelopedefective pNL.4.3.Luc-R⁻.E⁻ vector (Virology 1995 206:935-44) by furtherdeleting part of the HIV envelope protein.

Generation of pseudotyped virus particles in transiently transfectedHEK-293T cells.

Pseudotyped HCV GT1a and GT1b particles (HCVpp) and the pseudotyped VSVG particles (VSVpp) were generated from transiently transfected HEK-293Tcells (ATCC cat# CRL-573). For generating HCVpp, the HEK-293T cells weretransfected with equal amounts of plasmids expressing the HCV envelopeproteins and the HIV packaging genome by using polyethylenimine(Polysciences cat#23966) as transfection reagent. For generating VSVpp,the HEK-293T cells were transfected with equal amounts of plasmidsexpressing VSV G and the HIV packaging genome by using polyethylenimine.24 hours after the transfection, the cell culture medium containing thetransfection mixture was replaced with fresh Dulbecco's Modified EagleMedium (DMEM-Glutamax-I; Invitrogen cat #10569-010) supplemented with10% Fetal Bovine Serum (Invitrogen cat #10082-147) and 2 mM L-glutamine(Invitrogen cat #25030-081). The supernatant was collected 48 hoursafter the transfection and filtered through a sterile 0.45 μm filter.Aliquots of the supernatant was frozen and stored at −80° C. until use.

Huh7-high CD81 cells with high CD81 expression level were enriched byflow cytometry sorting using FITC-labeled CD81 antibody JS-81 (BDBiosciences cat#561956) to allow more efficient HCV entry. The Huh7-highCD81 cells were cultured in Dulbecco's Modified Eagle Medium(DMEM-Glutamax-I; Invitrogen cat #10569-010). The medium wassupplemented with 10% Fetal Bovine Serum (Invitrogen cat #10082-147) and1% penicillin/streptomycin (Invitrogen cat #15070-063). Cells weremaintained at 37 C in a humidified 5% CO₂ atmosphere.

Determination of compound HCVpp entry inhibitory activity in Huh?-highCD81 cells.

Huh7-high CD81 cells were plated at a cell density of 8000 cells perwell in 96 well plates (Perkin Elmer, cat #6005660). Cells were platedin 100 μl of Dulbecco's Modified Eagle Medium (DMEM-Glutamax-I,Invitrogen Cat #10569-010) supplemented with 10% Fetal Bovine Serum(Invitrogen Cat #10082-147) and 1% penicillin/streptomycin (Invitrogencat #15070-063). Cells were allowed to equilibrate for 24 hours at 37 Cand 5% CO2 at which time compounds and pseudotyped viruses were added.On the day of the assay, HCVpp aliquots were thawed in 37° C. water bathand kept at 4° C. until use. Compounds (or medium as a control) werediluted in 3 fold dilution series in DMEM-Glutamax-I with 2% DMSO and 2%penicillin/streptomycin. The 100 μl plating medium in each culture wellwas removed followed by the addition of 50 μl compound dilutions and 50thawed HCVpp. Firefly luciferase reporter signal was read 72 hours afterthe addition of compounds and HCVpp using the Steady-Glo luciferaseAssay System (Promega, cat # E2520) following the manufacturer'sinstruction. EC50 values were defined as the compound concentration atwhich a 50% reduction in the levels of firefly luciferase reporter wasobserved as compared to control samples in the absence of compound andwas determined by non-linear fitting of compound dose-response data.

Determination of compound selectivity in Huh7-high CD81 cells.

Huh7 hCD81 cell assay plates and compound dilutions were set up in thesame format as in the HCVpp assay. 24 hours after cell plating, thawedVSVpp was diluted by 800 fold in DMEM-Glutamax-I supplemented with 10%fetal bovine serum. After removal of the cell plating medium from theculture wells, 50 μl compound dilutions and 50 μl diluted VSVpp wereadded to the wells. Firefly luciferase reporter signal was read 72 hoursafter the addition of compounds and VSVpp using the Steady-Gloluciferase Assay System (Promega, cat # E2520). EC50 values were definedas the compound concentration at which a 50% reduction in the levels offirefly luciferase reporter was observed as compared to control samplesin the absence of compound and was determined by non-linear fitting ofcompound dose-response data. The EC50 was approximated if maximumpercentage inhibition was less than 90% and more than 70%.Representative assay data can be found in Table II below:

TABLE II HCVpp GT-1a HCVpp GT-1b VSVpp Compound # (EC₅₀, M) (EC₅₀, M)(EC₅₀, M) 1 39.924 64.007 100 2 52.235 33.993 3 39.261 35.836 100 41.361 6.058 >100 5 8.634 9.215 9.797 6 3.548 10.32 86.001 7 8.206 13.668 9.029 100 9 2.988 7.039 10 1.525 9.871 11 29.265 100

The foregoing invention has been described in some detail by way ofillustration and example, for purposes of clarity and understanding. Itwill be obvious to one of skill in the art that changes andmodifications may be practiced within the scope of the appended claims.

Therefore, it is to be understood that the above description is intendedto be illustrative and not restrictive. The scope of the inventionshould, therefore, be determined not with reference to the abovedescription, but should instead be determined with reference to thefollowing appended claims, along with the full scope of equivalents towhich such claims are entitled.

All patents, patent applications and publications cited in thisapplication are hereby incorporated by reference in their entirety forall purposes to the same extent as if each individual patent, patentapplication or publication were so individually denoted.

The invention claimed is:
 1. A compound wherein said compound isN⁵-(3,5-Dichloro-phenyl)-1H-pyrazole-3,5-diamine;N⁵-(3,5-Dichloro-4-fluoro-phenyl)-1H-pyrazole-3,5-diamine;(3,5-Dichloro-phenyl)-(5-methyl-[1,3,4]oxadiazol-2-yl)-amine;N³-(3-Trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine;N⁵-(3,5-Dichloro-phenyl)-[1,2,4]oxadiazole-3,5-diamine;N³-(3,5-Dichloro-phenyl)-[1,2,4]oxadiazole-3,5-diamine;N⁵-(3-Chloro-5-trifluoromethyl-phenyl)-[1,2,4]oxadiazole -3,5-diamine;N³-(3-Chloro-5-trifluoromethyl-phenyl)-[1,2,4]oxadiazole-3,5-diamine;N-[4′-(3-Amino-[1,2,4]oxadiazol-5-ylamino)-6′-chloro-2′-trifluoromethyl-biphenyl-3-yl]-methanesulfonamide;N-[4′-(5-Amino-[1,2,4]oxadiazol-3-ylamino)-6′-chloro-2′-trifluoromethyl-biphenyl-3-yl]-methanesulfonamide;or N²-(3,5-Dichloro-phenyl)-oxazole-2,5-diamine, or a pharmaceuticallyacceptable salt thereof.
 2. A method for treating a Hepatitis C Virus(HCV) infection, comprising the step of administering to a patient inneed thereof a therapeutically effective amount of a compound of claim 1or a pharmaceutically acceptable salt thereof.
 3. A pharmaceuticalcomposition, comprising a therapeutically effective amount of a compoundaccording to claim 1, or a pharmaceutically acceptable salt thereof, anda pharmaceutically acceptable excipient.
 4. The method of claim 2,further comprising the step of administering a combination of antiviralagents that inhibits replication of HCV.
 5. The method of claim 2,further comprising the step of administering an immune system modulatoror an antiviral agent that inhibits replication of HCV, or a combinationthereof.
 6. The method of claim 5, wherein the immune system modulatoris an interferon or a chemically derivatized interferon.
 7. The methodof claim 5, wherein the antiviral agent is selected from the groupconsisting of a HCV protease inhibitor, a HCV polymerase inhibitor, aHCV helicase inhibitor, a HCV NS5A inhibitor, or any combinationthereof.